The objective of the proposed study is to develop and compare automated and computerized pyrolysis mass spectrometry (Py-MS) techniques for cell and tissue characterization using a highly defined frog embryo (Xenopus laevis) model. A second objective is to study early biochemical differentiation phenomena in embryonic cells and tissues. A recently constructed modular Py-MS system, available at the Biomaterials Profiling Center, will be automated and consecutively adapted to operation in various Py-MS modes including the basic Curie-point pyrolysis mode, a direct probe pyrolysis mode and a time-resolved pyrolysis mode. Furthermore, specialized computer programs will be written to maximize the information yield from each mode of operation and will include three-dimensional mapping of distance matrices, handling of large data matrices by minicomputer, and processing of time-resolved pyrolysis mass spectra. A continuing programming effort will address the development of an operator-interactive program package for analysis of Py-MS data by minicomputer. Analysis of frog embryo cells and tissues will involve the characterization of each individual cell at the 8, 16, 32 and 64 cell blastula stage, as well as of selected tissue fragments of the primordial brain at the neurula stage using the various Py-MS modes mentioned above. These analyses will afford a comparison of the relative potentials of different Py-MS approaches and provide insight into early biochemical differentiation phenomena not easily accessible to other techniques.